Pitaya-inspired Li Metal-free Prelithiation of silicon monoxide into anode materials for Li-ion batteries

Silicon monoxide (SiO), which has been verified as a potential anode material, can improve the energy density of Li-ion batteries (LIBs). These LIBs are crucial for the advancement of electric vehicles. However, the commercial application of SiO is severely limited due to poor initial Coulombic efficiency (ICE). In this study, we present a novel concept to enhance the ICE of silicon oxide-based anodes by collaboratively leveraging two distinct reaction theories: disproportionation reaction and the reaction between acidic oxide and alkali. Based on this concept, we utilize a chemical disproportionation-driven Li metal-free prelithiation method, enabling the in-situ growth of microcrystalline silicon and lithium silicate within amorphous silicon oxide, which bears a striking resemblance to pitaya seeds. This reaction yields unique lithium silicate and nano/micro-structured silicon surrounded by SiO (Si-SiO-LixSiOy multicomponents, PD-SiO). This can be demonstrated via transmission electron microscopy (TEM), Electron energy loss spectroscopy (EELS) or X-ray photoelectron spectroscopy (XPS). The reaction product, PD-SiO, exhibits remarkable properties, including high ICE (82.5 %), high charging capacity (1419 mAh g-1), and highly stable cycling performance (94.6 % capacity retention after 200 cycles at 0.5 A g-1). This study offers a new approach to enhance the initial Coulombic efficiency of silicon monoxide.